The present application relates to image display apparatuses used for enabling an observer to observe a two-dimensional image formed by an image forming device or the like.
There are some virtual image display apparatuses (image display apparatuses) each enabling an observer to observe a two-dimensional image formed by an image forming device in a form of a virtual image enlarged by a virtual optical system, as disclosed in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2005-521099 and Japanese Unexamined Patent Application Publication No. 2006-162767, for example.
FIG. 11 shows a conceptual diagram of an exemplary image display apparatus 410. The image display apparatus 410 includes an image forming device 411 having a plurality of pixels arranged in a two-dimensional matrix, a collimating optical system 412 collimating light emitted from the pixels of the image forming device 411, and an optical device 20 receiving the light collimated by the collimating optical system 412 into a plurality of directional rays traveling in different directions, guiding the light therethrough, and outputting the light. The optical device 20 includes a light-guiding plate 21 propagating thereinside the light received thereby with total reflection and outputting the propagated light, a first optical member 30 (a layer of reflective film, for example) reflecting the light received by the light-guiding plate 21 so as to cause the light received by the light-guiding plate 21 to be totally reflected inside the light-guiding plate 21, and a second optical member 40 (a multilayer reflective film, for example, in which a number of films are stacked) causing the light propagated with total reflection inside the light-guiding plate 21 to emerge from the light-guiding plate 21. Apparatuses, such as head-mounted displays (HMDs), that includes the image display apparatus 410 having the above-described configuration can be made lighter and smaller.